package com.yupi.yupicturebackend.service.impl;

import cn.hutool.core.util.NumberUtil;
import cn.hutool.core.util.ObjUtil;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.yupi.yupicturebackend.exception.BusinessException;
import com.yupi.yupicturebackend.exception.ErrorCode;
import com.yupi.yupicturebackend.exception.ThrowUtils;
import com.yupi.yupicturebackend.mapper.SpaceMapper;
import com.yupi.yupicturebackend.model.dto.space.analyze.*;
import com.yupi.yupicturebackend.model.entity.Picture;
import com.yupi.yupicturebackend.model.entity.Space;
import com.yupi.yupicturebackend.model.entity.User;
import com.yupi.yupicturebackend.model.vo.space.analyze.*;
import com.yupi.yupicturebackend.service.PictureService;
import com.yupi.yupicturebackend.service.SpaceAnalyzeService;
import com.yupi.yupicturebackend.service.SpaceService;
import com.yupi.yupicturebackend.service.UserService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 @author 边拾柱
 @date 2025/3/13 10:46
 */
@Service
public class SpaceAnalyzeServiceImpl extends ServiceImpl<SpaceMapper, Space> implements SpaceAnalyzeService {
    @Resource
    private UserService userService;
    @Resource
    private SpaceService spaceService;
    @Resource
    private PictureService pictureService;


    @Override
    public SpaceUsageAnalyzeResponse getSpaceUsageAnalyze(SpaceUsageAnalyzeRequest spaceUsageAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceUsageAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        boolean queryAll = spaceUsageAnalyzeRequest.isQueryAll();
        boolean queryPublic = spaceUsageAnalyzeRequest.isQueryPublic();
//        checkSpaceAnalyzeAuth(spaceUsageAnalyzeRequest, loginUser);
        if (queryAll || queryPublic) {
            checkSpaceAnalyzeAuth(spaceUsageAnalyzeRequest, loginUser);
            QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
            /**
             * 由于我们只需要获取图片存储大小，从数据库中查询时要指定 只查询需要的列，
             * 并且使用 mapper 的 selectObjs 方法直接返回 Object 对象，而不用封装为 Picture 对象，可以提高性能并节约存储空间。
             */
            queryWrapper.select("picSize");
            fillAnalyzeQueryWrapper(spaceUsageAnalyzeRequest, queryWrapper);
            List<Object> picSizes = pictureService.getBaseMapper().selectObjs(queryWrapper);
            long useTotalSzie = picSizes.stream().mapToLong(o -> (Long) o).sum();
            long usedCount = picSizes.size();
            SpaceUsageAnalyzeResponse spaceUsageAnalyzeResponse = new SpaceUsageAnalyzeResponse();
            spaceUsageAnalyzeResponse.setUsedCount(usedCount);
            spaceUsageAnalyzeResponse.setUsedSize(useTotalSzie);
            return spaceUsageAnalyzeResponse;
        } else {
            Long spaceId = spaceUsageAnalyzeRequest.getSpaceId();
            ThrowUtils.throwIf(spaceId == null || spaceId <= 0, ErrorCode.PARAMS_ERROR);
            Space space = spaceService.getById(spaceId);
            ThrowUtils.throwIf(space == null, ErrorCode.NOT_FOUND_ERROR, "空间不存在");
            checkSpaceAnalyzeAuth(spaceUsageAnalyzeRequest, loginUser);
            SpaceUsageAnalyzeResponse spaceUsageAnalyzeResponse = new SpaceUsageAnalyzeResponse();
            spaceUsageAnalyzeResponse.setUsedSize(space.getTotalSize());
            spaceUsageAnalyzeResponse.setUsedCount(space.getTotalCount());
            spaceUsageAnalyzeResponse.setMaxSize(space.getMaxSize());
            spaceUsageAnalyzeResponse.setMaxCount(space.getMaxCount());
            /**
             * 乘以100 求得是百分比
             */
            double sizeUsageRatio = NumberUtil.round(space.getTotalSize() * 100.0 / space.getMaxSize(), 2).doubleValue();
            double countUsageRatio = NumberUtil.round(space.getTotalCount() * 100.0 / space.getMaxCount(), 2).doubleValue();
            spaceUsageAnalyzeResponse.setSizeUsageRatio(sizeUsageRatio);
            spaceUsageAnalyzeResponse.setCountUsageRatio(countUsageRatio);
            return spaceUsageAnalyzeResponse;
        }
    }


    private void checkSpaceAnalyzeAuth(SpaceAnalyzeRequest spaceAnalyzeRequest, User loginUser) {
        // 检查权限
        if (spaceAnalyzeRequest.isQueryAll() || spaceAnalyzeRequest.isQueryPublic()) {
            // 全空间分析或者公共图库权限校验：仅管理员可访问
            ThrowUtils.throwIf(!userService.isAdmin(loginUser), ErrorCode.NO_AUTH_ERROR, "无权访问公共图库");
        } else {
            // 私有空间权限校验
            Long spaceId = spaceAnalyzeRequest.getSpaceId();
            ThrowUtils.throwIf(spaceId == null || spaceId <= 0, ErrorCode.PARAMS_ERROR);
            Space space = spaceService.getById(spaceId);
            ThrowUtils.throwIf(space == null, ErrorCode.NOT_FOUND_ERROR, "空间不存在");
            spaceService.checkSpaceAuth(loginUser, space);
        }
    }

    @Override
    public List<SpaceCategoryAnalyzeResponse> getSpaceCategoryAnalyze(SpaceCategoryAnalyzeRequest spaceCategoryAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceCategoryAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);

        // 检查权限
        checkSpaceAnalyzeAuth(spaceCategoryAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        // 根据分析范围补充查询条件
        fillAnalyzeQueryWrapper(spaceCategoryAnalyzeRequest, queryWrapper);

        // 使用 MyBatis-Plus 分组查询
        queryWrapper.select("category AS category", "COUNT(*) AS count", "SUM(picSize) AS totalSize").groupBy("category");

        // 查询并转换结果
        return pictureService.getBaseMapper().selectMaps(queryWrapper).stream().map(result -> {
            String category = result.get("category") != null ? result.get("category").toString() : "未分类";
            Long count = ((Number) result.get("count")).longValue();
            Long totalSize = ((Number) result.get("totalSize")).longValue();
            return new SpaceCategoryAnalyzeResponse(category, count, totalSize);
        }).collect(Collectors.toList());
    }


    @Override
    public List<SpaceTagAnalyzeResponse> getSpaceTagAnalyze(SpaceTagAnalyzeRequest spaceTagAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceTagAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);

        // 检查权限
        checkSpaceAnalyzeAuth(spaceTagAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        fillAnalyzeQueryWrapper(spaceTagAnalyzeRequest, queryWrapper);

        // 查询所有符合条件的标签
        queryWrapper.select("tags");
        List<String> tagsJsonList = pictureService.getBaseMapper().selectObjs(queryWrapper).stream().filter(ObjUtil::isNotNull).map(Object::toString).collect(Collectors.toList());

        // 合并所有标签并统计使用次数
        Map<String, Long> tagCountMap = tagsJsonList.stream().flatMap(tagsJson -> JSONUtil.toList(tagsJson, String.class).stream()).collect(Collectors.groupingBy(tag -> tag, Collectors.counting()));

        // 转换为响应对象，按使用次数降序排序
        return tagCountMap.entrySet().stream().sorted((e1, e2) -> Long.compare(e2.getValue(), e1.getValue())) // 降序排列
                .map(entry -> new SpaceTagAnalyzeResponse(entry.getKey(), entry.getValue())).collect(Collectors.toList());
    }


    @Override
    public List<SpaceSizeAnalyzeResponse> getSpaceSizeAnalyze(SpaceSizeAnalyzeRequest spaceSizeAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceSizeAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);

        // 检查权限
        checkSpaceAnalyzeAuth(spaceSizeAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();
        fillAnalyzeQueryWrapper(spaceSizeAnalyzeRequest, queryWrapper);

        // 查询所有符合条件的图片大小
        queryWrapper.select("picSize");
        List<Long> picSizes = pictureService.getBaseMapper().selectObjs(queryWrapper).stream().map(size -> ((Number) size).longValue()).collect(Collectors.toList());

//        // 定义分段范围，注意使用有序 Map
//        Map<String, Long> sizeRanges = new LinkedHashMap<>();
//        sizeRanges.put("<100KB", picSizes.stream().filter(size -> size < 100 * 1024).count());
//        sizeRanges.put("100KB-500KB", picSizes.stream().filter(size -> size >= 100 * 1024 && size < 500 * 1024).count());
//        sizeRanges.put("500KB-1MB", picSizes.stream().filter(size -> size >= 500 * 1024 && size < 1 * 1024 * 1024).count());
//        sizeRanges.put(">1MB", picSizes.stream().filter(size -> size >= 1 * 1024 * 1024).count());

        // 只需要遍历一次 picSizes 列表就可以按大小分别统计了。  上面的每个范围都需要单独遍历一次，数据量太大时，就很慢了
        // 初始化计数器
        long countLess100KB = 0;
        long count100KBTo500KB = 0;
        long count500KBTo1MB = 0;
        long countGreater1MB = 0;

        // 单次遍历统计所有范围
        for (Long size : picSizes) {
            if (size < 100 * 1024) {
                countLess100KB++;
            } else if (size < 500 * 1024) {
                count100KBTo500KB++;
            } else if (size < 1024 * 1024) {
                count500KBTo1MB++;
            } else {
                countGreater1MB++;
            }
        }

        // 使用LinkedHashMap保持顺序
        Map<String, Long> sizeRanges = new LinkedHashMap<>();
        sizeRanges.put("<100KB", countLess100KB);
        sizeRanges.put("100KB-500KB", count100KBTo500KB);
        sizeRanges.put("500KB-1MB", count500KBTo1MB);
        sizeRanges.put(">1MB", countGreater1MB);

        // 转换为响应对象
        return sizeRanges.entrySet().stream().map(entry -> new SpaceSizeAnalyzeResponse(entry.getKey(), entry.getValue())).collect(Collectors.toList());
    }


    @Override
    public List<SpaceUserAnalyzeResponse> getSpaceUserAnalyze(SpaceUserAnalyzeRequest spaceUserAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceUserAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);
        // 检查权限
        checkSpaceAnalyzeAuth(spaceUserAnalyzeRequest, loginUser);

        // 构造查询条件
        QueryWrapper<Picture> queryWrapper = new QueryWrapper<>();

        Long userId = spaceUserAnalyzeRequest.getUserId();
        queryWrapper.eq(ObjUtil.isNotNull(userId), "userId", userId);
        fillAnalyzeQueryWrapper(spaceUserAnalyzeRequest, queryWrapper);

        // 分析维度：每日、每周、每月
        String timeDimension = spaceUserAnalyzeRequest.getTimeDimension();
        switch (timeDimension) {
            case "day":
                queryWrapper.select("DATE_FORMAT(createTime, '%Y-%m-%d') AS period", "COUNT(*) AS count");
                break;
            case "week":
                /**
                 * 202511  就表示2025年11月，即202511
                 */
                queryWrapper.select("YEARWEEK(createTime) AS period", "COUNT(*) AS count");
                break;
            case "month":
                queryWrapper.select("DATE_FORMAT(createTime, '%Y-%m') AS period", "COUNT(*) AS count");
                break;
            default:
                throw new BusinessException(ErrorCode.PARAMS_ERROR, "不支持的时间维度");
        }

        // 分组和排序
        queryWrapper.groupBy("period").orderByAsc("period");

        // 查询结果并转换
        List<Map<String, Object>> queryResult = pictureService.getBaseMapper().selectMaps(queryWrapper);
        return queryResult.stream().map(result -> {
            String period = result.get("period").toString();
            Long count = ((Number) result.get("count")).longValue();
            return new SpaceUserAnalyzeResponse(period, count);
        }).collect(Collectors.toList());
    }


    @Override
    public List<Space> getSpaceRankAnalyze(SpaceRankAnalyzeRequest spaceRankAnalyzeRequest, User loginUser) {
        ThrowUtils.throwIf(spaceRankAnalyzeRequest == null, ErrorCode.PARAMS_ERROR);

// 仅管理员可查看空间排行
        ThrowUtils.throwIf(!userService.isAdmin(loginUser), ErrorCode.NO_AUTH_ERROR, "无权查看空间排行");

// 构造查询条件
        QueryWrapper<Space> queryWrapper = new QueryWrapper<>();
        queryWrapper.select("id", "spaceName", "userId", "totalSize")
                .orderByDesc("totalSize")
                .last("LIMIT " + spaceRankAnalyzeRequest.getTopN()); // 取前 N 名

// 查询结果
        return spaceService.list(queryWrapper);
    }


    private static void fillAnalyzeQueryWrapper(SpaceAnalyzeRequest spaceAnalyzeRequest, QueryWrapper<Picture> queryWrapper) {
        if (spaceAnalyzeRequest.isQueryAll()) {  //查所有 默认就是没有条件约束即可
            return;
        }
        if (spaceAnalyzeRequest.isQueryPublic()) {
            queryWrapper.isNull("spaceId");
            return;
        }
        Long spaceId = spaceAnalyzeRequest.getSpaceId();
        if (spaceId != null) {
            queryWrapper.eq("spaceId", spaceId);
            return;
        }
        throw new BusinessException(ErrorCode.PARAMS_ERROR, "未指定查询范围");
    }


}
